Stand up bag and method of manufacturing the same

ABSTRACT

A method for manufacturing a stand up bag having an indented bottom wall includes the steps of forming a tube of material and sealing the end of the tube. The sealed end is then moved up with respect to the sidewall to form a downwardly-extending rim. Portions of the rim are then welded to hold the bottom wall in this position.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional PatentApplication serial No. 60/323,611 filed Sep. 19, 2001; the disclosuresof which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention generally relates to storage containers inthe field of flexible bags and, more particularly, to stand-up bagshaving indented bottom walls. Specifically, the present inventionrelates to stand-up bags that are fabricated from a flexible materialwherein the bottom wall of the bag is reformed into an indented cup witha welded downwardly-projecting rim.

[0004] b 2. Background Information

[0005] Various products such as snack foods are sold to consumers inthin-walled flexible bags fabricated from a polymer material. These bagsare typically formed from a tube of material that is sealed with spacedflanges. The storage compartment between the flanges is filled with theproduct.

[0006] An undesirable aspect with these bags is that the lower sealedflange prevents the bag from standing in an upright position. The bagthus tips over on its side after it has been opened. The users of thesebags desire a bag configuration that will stand on end after the bag isopened.

[0007] Different types of stand up bags are known in the art. One typeof stand up bag is fabricated from a relatively thick foil material withprotruding flanges extending from opposed sides of the bag. Such bagshave gained acceptance for certain products but are generallyundesirable because the thick material cannot be used for snack foodbags without undesirably increasing the cost of the bag. The art thusdesires a stand up bag structure and a method for manufacturing thestand up bag wherein the bag may be formed from a relativelyinexpensive, thin material.

BRIEF SUMMARY OF THE INVENTION

[0008] One embodiment of the invention provides a stand up bag having anindented, cup-shaped bottom wall that allows the bag to stand up. Alower rim is formed between the bottom wall and the sidewall. Portionsof the rim are welded so that the bottom wall is held in its indentedposition. The invention provides numerous different weld patterns forthe lower rim.

[0009] Another embodiment of the invention provides a method formanufacturing a stand up bag having an indented bottom wall. The methodincludes the steps of forming a tube of material and sealing the end ofthe tube. The sealed end is then moved up with respect to the sidewallto form a downwardly-extending rim. Portions of the rim are then weldedto hold the bottom wall in this position.

[0010] A further embodiment of the invention provides an apparatus forforming a stand up bag having an indented bottom wall. The inventionprovides three embodiments of the apparatus for reforming the bottomwall into the indented cup. Each embodiment of the apparatus generallyincludes a bottom former, an inside dome former, and a reform welderthat cooperate to reform the bottom wall and to weld the lower rim tohold the bottom wall in place.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0011]FIG. 1 is a perspective view of the stand up bag of the presentinvention.

[0012]FIG. 2 is a front view of FIG. 1.

[0013]FIG. 3 is a side view of FIG. 1.

[0014]FIG. 4 is a bottom view of FIG. 1.

[0015]FIG. 5 is a section view taken along line 5-5 of FIG. 4.

[0016] FIGS. 6A-6D shown four different exemplary shapes for the bag ofthe invention.

[0017] FIGS. 7A-7D show four different exemplary weld patterns for anoval-shaped bag.

[0018]FIG. 8 is a front view of the first embodiment of the apparatusfor forming the stand up bag of the invention.

[0019]FIG. 9 is another front view of the apparatus for the stand up bagof the invention.

[0020]FIG. 10 is a top view of a portion of the apparatus.

[0021]FIG. 11 is a perspective view of the reform collar used to formthe rim of the bag.

[0022]FIG. 12 is a front view showing the first step of the firstembodiment of the method of the invention.

[0023]FIG. 13 is a front view showing the second step of the firstembodiment of the method of the invention.

[0024]FIG. 14 is a front view showing the third step of the firstembodiment of the method of the invention.

[0025]FIG. 15 is a front view showing the fourth step of the firstembodiment of the method of the invention.

[0026]FIG. 16 is a front view of the second embodiment of the apparatusfor forming the stand up bag of the invention.

[0027]FIG. 17 is a front view showing the first step of the secondembodiment of the method of the invention.

[0028]FIG. 18 is a front view showing the second step of the secondembodiment of the method of the invention.

[0029]FIG. 19 is a front view showing the third step of the secondembodiment of the method of the invention.

[0030]FIG. 20 is a front view showing the fourth step of the secondembodiment of the method of the invention.

[0031]FIG. 21 is a front view showing the first step of the thirdembodiment of the method of the invention.

[0032]FIG. 22 is a front view showing the second step of the thirdembodiment of the method of the invention.

[0033]FIG. 23 is a front view showing the third step of the thirdembodiment of the method of the invention.

[0034]FIG. 24 is a front view showing the fourth step of the thirdembodiment of the method of the invention.

[0035] Similar numbers refer to similar parts throughout thespecification.

DETAILED DESCRIPTION OF THE INVENTION

[0036] A first embodiment of the stand up bag according to the presentinvention is indicated generally by the numeral 10 in the accompanyingdrawings. Bag 10 includes a continuous sidewall 12 and an indentedbottom wall 14 that cooperate to define a storage compartment forholding items. As shown in FIG. 5, bottom wall 14 is disposed transverseto sidewall 12 and may be substantially perpendicular to the portions ofsidewall 12 adjacent bottom wall 14. The structure of bottom wall 14allows bag 10 to stand in an upright configuration without tipping over.Bag 10 may have any of a variety of shapes such as the exemplary ovalshape shown in the drawings. In other embodiments, the cross section(looking down along the longitudinal axis of the bag) of bag 10 may berectangular, diamond, or round as shown in FIGS. 6A-6D. Other bag shapesare also within the scope of the invention.

[0037] A downwardly projecting rim 16 is formed between sidewall 12 andbottom wall 14. Rim 16 is welded with a plurality of welds 18 that holdthe shape of rim 16 and indented bottom wall 14 while bag 10 is in use.Welds 18 also keep bottom wall 14 disposed substantially perpendicularto sidewall 12. In one embodiment of the invention, bottom wall 14 isindented 1 ½ inches with respect to sidewall 12 as indicated bydimension line 20 in FIG. 5. The 1 ½ inch indentation dimension (20) hasbeen found to function well with medium, large, and oversize snack foodbags. Other indentation dimensions will also function with bag 10. Forinstance, the indentation dimension may be as short as ¼ inch and astall as 2½ inch.

[0038] Bag 10 may be provided in a wide variety of shapes and rim 16 maybe welded in a wide variety of weld configurations. FIGS. 6A-6D showbottom views of different shapes of bag 10. FIG. 6A shows oval. FIG. 6Bshows rectangular. FIG. 6C shows diamond and FIG. 6D shows a round bag.In each of these drawings, the thick line along rim 16 represents thelocation of weld 18 with each drawing representing one of the variety ofpossible weld patterns that may be used to hold rim 16 in position.FIGS. 7A-7D show four weld patterns used with an oval bag. Each of theseweld patterns may be used with each of the shapes depicted in FIGS.6A-6D and any bag shapes known to those skilled in the art. In theexemplary embodiment, the ratio of the total weld lengths to theperimeter of rim 16 should be about 75 percent. In other embodiments ofthe invention, the ratio may be as small as 5% and as large as 95%.Small pinch welds may be used that are not long in length.

[0039] Bag 10 further includes a top closure seam 30 and a bottomclosure seam 32. Seams 30 and 32 may be positioned with respect to welds18 as shown in the drawings or turned at any of a variety of angles withrespect to welds 18.

[0040] Bag 10 may thus stand on rim 16 or bottom wall 14. Sidewall 12 isformed from a continuous tube or a tube formed with a longitudinaloverlap seam so that sidewall 12 does not have any protruding flanges.Bag 10 may be fabricated from any of the weldable materials known in theart of manufacturing snack food bags. The structure of the inventionallows stand up bag 10 to be manufactured from a thin, flexible chip-bagmaterial.

[0041] A first embodiment of the apparatus 100 for manufacturing bag 10is depicted generally in FIGS. 8-11 for the purpose of introducing someof its elements. FIGS. 8 and 9 depicts a front view of apparatus 100with some elements depicted in section and other elements exploded forclarity. Apparatus 100 generally includes a collar 102 that extends downfrom the end of a former 104. Former 104 is used to form a tube 106 (seefor example FIG. 12) of material that is used to form the walls of bag10. The use of former 104 and the process of making tube 106 is known tothose skilled in the art and will not be described here in detail.Collar 102 has a cross section that generally matches the shape offormer 104 and thus generally matches the shape of the cross section ofbag 10. In the exemplary embodiment of the invention depicted in FIGS.8-11, collar 102 is round and is used to form round bags 10 as shown inFIG. 6D.

[0042] Collar 102 is used to form rim 16 by bending the material of bag10 over collar 102. The upper portion 110 of collar 102 is connected toformer 104 with the lower portion 112 of collar 102 extending down freeof former 104 so that the material of tube 106 may be wrapped aroundlower portion 112. The body of lower portion 112 defines a plurality ofweld openings 114 positioned at the locations where welds 18 will beformed in rim 16. Openings 114 allow welders 120 to weld the desiredareas of rim 16 during the process of forming bag 10.

[0043] Welders 120 are carried by a first base member 118. Base member118 may include several elements as shown in the drawings. For instance,base member 118 may include the lower plate and an outer ring. Base 118is divided into halves that move apart to allow bag 10 to pass throughbase 118 as described in more detail below. In other embodiments of theinvention, base 118 may be divided into other numbers of elements suchas three, four, five, etc. The structure and operation of welders 120are known to those skilled in the art. Welders 120 are generallyconfigured to melt the material of bag 10 without burning and withoutmelting a hole in the material. Welds 18 thus do not break the integrityof bag 10 such that bag 10 remains hermetically sealed.

[0044] In the exemplary embodiment of apparatus 100, each welder 120 ismovable between a resting position and a welding position with welder120 being biased toward the resting position. Welder 120 may be biasedwith a spring or other mechanism known to those skilled in the art.

[0045] A guide 122 (FIG. 12) is associated with each welder 120. Eachguide 122 is mounted to first base 118. Base 118 may include blocks ordefine an opening that defines a slide path for guide 122. Each guide122 is movable between first and second positions within the slide pathdefined by base 118. When guide 122 is in the first position, welder 120is in the resting position. As guide 122 moves to the second position,welder 120 is moved inwardly to the welding position. In the exemplaryembodiment of the invention, each guide 122 includes an angled surface124 that engages a corresponding angled surface 126 defined by a portionof welder 120. The engagement of angled surfaces 124 and 126 as guide122 moves upwardly cause welder 120 to move inwardly. This configurationallows the movement and positioning of welders 120 to be preciselycontrolled and adjusted. The movement of guides 122 may be controlled byany of a variety of actuators (not shown) and linkages as are needed.For instance, an actuator may be associated with each guide 122 or asuitable linkage may be provided that links each guide 122 to a singleactuator. In other embodiments, guides 122 may be removed and themovement of welders 120 may be achieved directly with actuators.

[0046] Apparatus 100 further includes a dome former 130 that helps formbottom wall 14 during the reform process. Dome former 130 may be mountedto base 118. Former 130 is aligned with collar 102 and may be concentricwith collar 102 so that they may cooperate during the reform processdescribed below. Dome former 130 includes a sidewall 132 having astraight lower portion and a curved portion that merges with arelatively flat upper wall 134. Sidewall 132 is aligned with welders 120so that portions of rim 16 may be pinched between or pinched adjacentsidewall 132 and welder 120 to form welds 18. The thickness of domeformer 130 is substantially equal to the height of bottom wall 14 asindicted by dimension 20 in FIG. 5.

[0047] Dome former 130 is divided into the same number of pieces as base118 so that former 130 may be moved out of the way as described below.In the exemplary embodiment, dome former 130 is divided into two pieces.

[0048] Apparatus 100 further includes a set of upper seal welding jaws140 and a set of bottom seal welding jaws 142. Jaws 140 and 142 includeopposed members that are adapted to cooperate to form seals 30 and 32.Upper seal welding jaws 140 are used to form seal 32 while bottom sealwelding jaws 142 are used to form seal 30. Jaws 140 and 142 may also beused to sever the material of tube 106. The structure and operation ofjaws 140 and 142 are known to those skilled in the bag forming art.

[0049] In apparatus 100, base 118 is configured to be moved upwardlytoward collar 102 with actuators 150 such as the air cylinders depictedin the drawings. Base 118 rides on guides 154 between the disengagedposition depicted in FIGS. 12, 14, and 15 and the engaged positiondepicted in FIG. 13. In the engaged position, collar 102 is disposedadjacent wall 132 where welders 120 may be moved inwardly to the weldingposition where the inner end of welder 120 is disposed adjacent wall132. Welders 120 and dome former 130 move with base 118 between thesepositions.

[0050] A first method for forming bag 10 is depicted in FIGS. 12-15 andis performed with apparatus 100. In FIG. 12, a finished bag 10 isdepicted at the bottom of the drawing with the lower portion of anotherbag beginning to be formed. At this point, bottom seal welding jaws 142have just cut bag 10 away from tube 106 so that the next bag may beformed.

[0051] In this position, welders 120 and dome former 130 are spaced fromcollar 102 in the disengaged position. Tube 106 has been drawn overformer 104 and collar 102 with a portion of tube 106 being positionedbetween jaws 140 and 142. Jaws 140 and 142 clamp together to form seals30 and 32 and to sever tube 106 between seals 30 and 32. After tube 106is cut to form bag 10 at the bottom of the page, jaws 140 and 142 areopened slightly (such as ⅛th inch) to allow the lower bag to drop fromapparatus 100.

[0052] At this point, the material 160 that is being placed into bags 10starts filling the bag being formed through former 104 and collar 102.Actuators 150 then start moving dome former 130 and welders 120 uptoward the engaged position depicted in FIG. 13. Dome former 130 bendstube 106 around the lower edge of collar 102 to form rim 16. Welders 120are then moved to the welding position to form welds 18.

[0053] After welds 18 are formed, welders 120 and jaws 140/142 move downto the disengaged position while moving to an open position as depictedin FIG. 14. Tube 106 continues to move down through these open elementswhile material 160 continues to be dispensed. Tube 106 moves down untilan appropriate amount of material 160 has been dispensed. Tube 106 thencontinues to move to provide slack for jaws 140 and 142. Once enoughslack is provided, jaws 140 and 142 move inwardly to form seals 30 and32 and to cut the finished bag 10 from tube 106 as depicted in FIG. 15.

[0054] The second embodiment of the apparatus of the present inventionis indicated generally by the numeral 200 in FIGS. 16-20. Apparatus 200includes many of the same elements as apparatus 100 and the samereference numbers are used to identify these elements. Apparatus 200differs from apparatus 100 in that welders 120 and dome former 130 donot move up and down and actuators 150 and guides 154 have been removed.In apparatus 200, collar 102 and former 104 move down from thedisengaged position of FIG. 17 to the engaged position of FIG. 18 toform welds 18.

[0055] A second method for forming bag 10 is depicted in FIGS. 17-20 andis performed with apparatus 200. In FIG. 17, a finished bag 10 isdepicted at the bottom of the drawing with the lower portion of anotherbag beginning to be formed. At this point, bottom seal welding jaws 142have just cut bag 10 away from tube 106 so that the next bag may beformed.

[0056] In this position, welders 120 and dome former 130 are spaced fromcollar 102 with collar 102 in the disengaged position. Tube 106 has beendrawn over former 104 and collar 102 with a portion of tube 106 beingpositioned between jaws 140 and 142. Jaws 140 and 142 clamp together toform seals 30 and 32 and to sever tube 106 between seals 30 and 32.After tube 106 is cut to form bag 10 at the bottom of the page, jaws 140and 142 are opened slightly to allow the lower bag to drop fromapparatus 100.

[0057] At this point, the material 160 that is being placed into bags 10may start entering the bag through former 104. An actuator (not shown)then starts moving collar 102 and former 104 down from the disengagedposition to the engaged position depicted in FIG. 18. Dome former 130bends tube 106 around the lower edge of collar 102 to form rim 16.Welders 120 are then moved to the welding position to form welds 18.

[0058] After welds 18 are formed, collar 102 and former 104 moves up tothe disengaged position while jaws 140 and 142 and welders 120 move toan open position as depicted in FIG. 19. Tube 106 continues to move downwhile material 160 continues to be dispensed. Tube 106 continues to movedown until an appropriate amount of material 160 has been dispensed.Tube 106 then continues to move to provide slack for jaws 140 and 142.Once enough slack is provided, jaws 140 and 142 move inwardly to formseals 30 and 32 and to cut the finished bag 10 from tube 106 as depictedin FIG. 20.

[0059] The second embodiment of the apparatus of the present inventionis indicated generally by the numeral 300 in FIGS. 21-24. Apparatus 300includes many of the same elements as apparatus 100 and the samereference numbers are used to identify these elements. Apparatus 300differs from apparatus 100 and 200 in that both welders 120 and domeformer 130 move up with collar 102 and former 104 moving down.

[0060] A third method for forming bag 10 is depicted in FIGS. 21-24 andis performed with apparatus 300. In FIG. 21, a finished bag 10 isdepicted at the bottom of the drawing with the lower portion of anotherbag beginning to be formed. At this point, bottom seal welding jaws 142have just cut bag 10 away from tube 106 so that the next bag may beformed.

[0061] In this position, welders 120 and dome former 130 are spaced fromcollar 102 with collar 102 in the disengaged position. Tube 106 has beendrawn over former 104 and collar 102 with a portion of tube 106 beingpositioned between jaws 140 and 142. Jaws 140 and 142 clamp together toform seals 30 and 32 and to sever tube 106 between seals 30 and 32.After tube 106 is cut to form bag 10 at the bottom of the page, jaws 140and 142 are opened slightly to allow the lower bag to drop fromapparatus 100.

[0062] At this point, the material 160 that is being placed into bags 10may start entering the bag through former 104. An actuator (not shown)then starts moving collar 102 and former 104 down from the disengagedposition to the engaged position depicted in FIG. 22. At the same time,actuators 150 move dome former 130 and welders 120 up toward the engagedposition depicted in FIG. 22. Dome former 130 bends tube 106 around thelower edge of collar 102 to form rim 16. Welders 120 are then moved tothe welding position to form welds 18.

[0063] After welds 18 are formed, collar 102 and former 104 move up tothe disengaged position while jaws 140 and 142 and welders 120 move toan open position as depicted in FIG. 23. Tube 106 continues to move downwhile material 160 continues to be dispensed. Tube 106 continues to movedown until an appropriate amount of material 160 has been dispensed.Tube 106 then continues to move to provide slack for jaws 140 and 142.Once enough slack is provided, jaws 140 and 142 move inwardly to formseals 30 and 32 and to cut the finished bag 10 from tube 106 as depictedin FIG. 20.

[0064] Each of these methods forms bags at a rate that is only slightlyslower than—or the same as—prior art bag manufacturing processes. Themethods allow rim 16 to be formed while the bag is being filled withmaterial 160 so that extra time is not needed for the welding step.

[0065] In the foregoing description, certain terms have been used forbrevity, clearness, and understanding. No unnecessary limitations are tobe implied therefrom beyond the requirement of the prior art becausesuch terms are used for descriptive purposes and are intended to bebroadly construed.

[0066] Moreover, the description and illustration of the invention is anexample and the invention is not limited to the exact details shown ordescribed.

1. A method of forming a bag comprising the steps of: (a) providing atube of material that will be used to form the body of the bag; (b)closing a portion of the tube to form the bottom closure seam of thebag; (c) indenting the bottom closure seam of the bag with respect tothe tube to define a rim and a bottom wall; and (d) welding at least oneportion of the rim.
 2. The method of claim 1, further comprising thestep of filling the tube with material after step (b).
 3. The method ofclaim 2, further comprising the step of filling the tube with materialduring step (c).
 4. The method of claim 2, further comprising the stepof filling the tube with material during step (d).
 5. The method ofclaim 1, wherein step (d) includes the step of welding a plurality ofspaced locations about the rim.
 6. The method of claim 1, wherein step(c) includes the steps of: providing a bottom former; and moving thebottom former up into the tube.
 7. The method of claim 1, wherein step(c) includes the steps of: providing a bottom former; and moving thetube down onto the bottom former.
 8. The method of claim 1, wherein step(c) includes the steps of: providing a bottom former; and simultaneouslymoving the tube down onto the bottom former and moving the bottom formerup into the tube.
 9. The method of claim 1, further comprising the stepsof: providing a former that performs step (c); and passing the filledtube through the former after step (d).
 10. The method of claim 1,further comprising the steps of: passing the tube of material over acollar that defines a plurality of weld openings; and welding the rimportions at the weld openings of the collar.
 11. A method of forming abag comprising the steps of: (a) forming a tube of weldable materialhaving a leading end; (b) sealing the leading end to itself to form thebottom closure seam of the bag; (c) filling the tube with material toprovide a filled tube; (d) indenting the bottom closure seam withrespect to the tube of material to define a rim and a bottom wall of thebag; (e) welding a plurality of rim portions to create a plurality ofspaced welds along the rim; and (f) sealing another portion of the tubeof material to form the top closure seam of the bag and a sealed filledbag.
 12. The method of claim 11, wherein step (d) occurs during step(c).
 13. The method of claim 11, wherein step (f) of one bagsimultaneously performs step (b) for the next bag to be formed.
 14. Themethod of claim 11, further comprising the steps of: sealing the leadingend of the tube of material with a welding jaws; and passing the filledtube through the welding jaws after step (d).
 15. The method of claim11, further comprising the steps of: passing the tube of material over acollar that defines a plurality of weld openings; and welding the rimportions at the weld openings of the collar.
 16. The method of claim 15,further comprising the steps of: providing a welder for each weld; andmoving the welder during step (e) in a direction substantiallytransverse to the longitudinal direction of the tube of material. 17.The method of claim 11, further comprising the steps of: providing aformer that performs step (d); and passing the filled tube through theformer after step (d).
 18. The method of claim 11, wherein step (d)includes the steps of: providing a bottom former; and moving the bottomformer up into the tube.
 19. The method of claim 11, wherein step (d)includes the steps of: providing a bottom former; and moving the tubedown onto the bottom former.
 20. The method of claim 11, wherein step(d) includes the steps of: providing a bottom former; and simultaneouslymoving the tube down onto the bottom former and moving the bottom formerup into the tube.